The following error handling is broken due to signedness.
int file_size;
uint32_t tag_bytes;
int64_t tag_start;
...
tag_start = file_size - tag_bytes - APE_TAG_FOOTER_BYTES;
if (tag_start < 0) { ... }
Note that tag_bytes is unsigned, which makes the right-hand side of
`tag_start = ...' unsigned, too. The 32-bit unsigned value is then
zero-extended to 64 bits. Therefore, tag_start must be non-negative,
and the check (tag_start < 0) is always false, which breaks the error
handling. This patch fixes the check.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
return 0;
}
- tag_start = file_size - tag_bytes - APE_TAG_FOOTER_BYTES;
- if (tag_start < 0) {
+ if (tag_bytes > file_size - APE_TAG_FOOTER_BYTES) {
av_log(s, AV_LOG_ERROR, "Invalid tag size %u.\n", tag_bytes);
return 0;
}
+ tag_start = file_size - tag_bytes - APE_TAG_FOOTER_BYTES;
fields = avio_rl32(pb); /* number of fields */
if (fields > 65536) {